单项选择题 计数器74HC160具有预置数的功能，LD=0且在CP下升沿时预置数。 A、正确 B、错误

未知题型 单项选择题第31-50小题，每小题1分。共20分。下列每题给出的四个选项中，只有一个选项是符合题目要求的。请在答题卡上将所选项的字母涂黑。下列行为中，属于民事法律行为的是( )。D.催告

未知题型 Mr. White lived in Florida and owned a company therE.Some computers were made in his company. He was nice to his employees(雇员)and often had a joke with them. They liked him very much and worked harD.So he paid them a lot.Mr. White had tots of work to do and often went to bed late at night. His friends advised him to do some exercisE.He thought he was strong and didn't agree with them. But one day he fell in a faint(晕倒) while he was working in his officE.He was sent to a hospital at once and the doctors examined him carefully. They found something was wrong with his heart and he had to be in hospital. Several months later he returned home and asked his son to manage the company.Once his daughter wanted to travel in AustraliA.The old man decided to go there with her. As he went to the country for the first time, he was interested in all. He played well, had a good sleep and visited some places of interest. And one day they visited a farm. It was big and beautiful. Cows and sheep could be seen everywherE.Pointing to a cow, Mr. White asked, 'What's this?''Haven't you seen a cow?' the guide asked in surprisE.'Cow?' Mr. White said with a smilE.'A cow in our country is five times(倍)as big as it!'Having heard this, all the visitors began to laugh. After a while he saw a kangaroo (袋鼠) and asked again, 'What's that?''It' s a flea(跳蚤), sir. 'answered the guidE.The employees worked hard because ______.A.Mr. White was kind to themB.Mr. White had a companyC.Mr. White often had a joke with themD.they liked to use computers